One in three American kids is overweight or obese, but don’t tell their parents that. New research in the journal Pediatrics finds that Mom and Dad recoil when doctors describe their children as “fat” or “obese.” They would prefer to hear that their kids are hovering at an “unhealthy weight.”

With 2 million U.S. children classified as extremely obese, it’s impossible to ignore kids’ growing girth. But researchers at the Rudd Center for Food Policy and Obesity at Yale University are suggesting that there are better, more sensitive ways to discuss the issue with parents and children.

“Many people find the term ‘fat’ to be pejorative and judgmental,” says Rebecca Puhl, the study’s lead author and Rudd’s director of research. “A lot of the time, providers have positive intentions, but the language they use can be seen as blaming, accusatory and not helpful.”

Researchers asked 445 parents — who were a mix of overweight, obese and normal-weight moms and pops — to weigh in on 10 commonly used terms to describe weight. The parents cringed at “chubby,” “fat,” “obese” and “extremely obese,” while preferring the unjudgmental “weight.”

For example, they’d welcome a doctor approaching the subject by saying simply, Let’s talk about your weight, rather than, Let’s talk about how fat you’ve gotten. The surveyed parents, 44% of whom had at least one overweight child, also approved of the terms “high BMI” (body-mass index) and “unhealthy weight.”

Not surprisingly, parents indicated that the terms they found most offensive were also the most stigmatizing and least likely to cause their children to actually take action to lose weight.

The study was prompted in part by a comment last year by a British public-health minister who recommended that health providers in the United Kingdom call obese patients “fat” in order to goad them into losing weight. The Pediatrics research, says Puhl, shows that such an approach doesn’t work. “Parents were saying, No, ‘fat’ isn’t motivating at all,” she says.

Doctors, for their part, should just ask parents and children what language they prefer. In line with sensitivity training that Rudd has developed for practitioners, physicians should kick off the conversation by saying, I’d like to have a conversation about your weight. Are there specific terms you’d like me to use?

Researchers also asked parents how they would respond if they felt their child had been stigmatized by a doctor due to his or her weight. Half responded they would ask the physician to use more sensitive language, while 35% said they’d seek out a new practice. Thirty-seven percent said they would feel upset or embarrassed, and 36% indicated they’d put their child on a strict diet. Strict diets, however, are not typically recommended for children. Instead, they’re advised to exercise more while eating less junk food and more healthy offerings.

Weight stigma, of course, is alive and well in our society. Our culture values thinness, and research shows even health-care providers tend to believe overweight people are lazy and undisciplined.

“There seems to be a widespread public perception that stigma will motivate people to lose weight, when the research shows that the opposite is true,” says Puhl. Both children and adults, for example, are more likely to engage in unhealthy eating behaviors, such as binging, and to avoid exercise and eat more if they’re stigmatized. That’s not unusual considering that overeating is a common coping strategy people use when they feel stressed.

“Instead of instilling shame,” says Puhl, “we want to provide support to patients to become healthier.”

Bonnie Rochman is a reporter at TIME. Find her on Twitter at @brochman. You can also continue the discussion on TIME‘s Facebook page and on Twitter at @TIME.